Generally, a cleaner such as a vacuum cleaner and a steam cleaner is a device that uses a suction motor installed inside a main body to suck up air including foreign material such as dust, uses a filter inside the main body to remove the foreign material from the air, and discharge the filtered air.
The cleaner may be classified into a canister type in which a suction nozzle for sucking up dust is provided separately from the main body and connected by a connector and an upright type in which a suction nozzle is rotationally connected with the main body.
Generally, a cleaner includes a main body having a suction motor, a suction nozzle configured to suck up air including foreign material of a floor surface, and an air pipe configured to move the air sucked to the suction nozzle to the main body. In this case, while a user moves the suction nozzle, the main body moves along with the suction nozzle.
However, in order for a user to move a cleaner, a force corresponding to a friction force on the bottom surface of the main body is needed, and thus the movement of the cleaner is not easy. That is, since the cleaner does not have a power system for moving the main body, the user should directly move the main body or pull the air pipe to move the main body. In particular, when the user pulls the air pipe to move the main body, a failure may occur such as damage to a pipe connector.
A conventional autonomous mobile cleaner employs a technique of utilizing ultrasonic sensors in a foreign material suction nozzle and a main body, as described the following patent document 1. However, in this case, when there is an obstacle between an ultrasonic transmission unit and an ultrasonic reception unit, the reception of an ultrasonic signal is impossible. In addition, the ultrasonic transmission unit and the ultrasonic reception unit may be blocked by a user, etc. Furthermore, when the cleaner is used in a complicated indoor space, malfunction may occur due to ultrasonic signals reflected by surrounding objects.
Accordingly, there is a need for technology to solve such problems.